Merge pull request #578 from tarunon/feature/drive_to_variable

Adding drive to Variable operator to Driver

RxCocoa/Common/CocoaUnits/Driver/Driver+Subscription.swift

@@ -26,6 +26,19 @@ extension DriverConvertibleType {
         return self.asObservable().subscribe(observer)
     }
 
+    /**
+    Creates new subscription and sends elements to variable.
+
+    - parameter variable: Target variable for sequence elements.
+    - returns: Disposable object that can be used to unsubscribe the observer from the variable.
+    */
+    @warn_unused_result(message="http://git.io/rxs.ud")
+    public func drive(variable: Variable<E>) -> Disposable {
+        return drive(onNext: { e in
+            variable.value = e
+        })
+    }
+
     /**
     Subscribes to observable sequence using custom binder function.